Control system for motion picture apparatus



Nov. 10, 1942- c. L. LOOTENS ETAL CONTROL SYSTEM FOR MOTION PICTUREAPPARATUS Filed Dec.

27, 1940 2 Sheets-Sheet l fiscoka'sz Suki/1V6 firm vs 3 bwsesa uINVENTOR:

CHARZES 1,7. Lam-Ems, 1 By Woo/v T/Vhrso/v,

' ATTORNEYS.

2 Sheets-Sheet 2 INVENTOR: CHARLES .5. L00 rE/vs, BY Hiya/v0. Tk'qrsolvA TTORNEYS.

Filed Dec. 2'7, 1940 C. L. LOOTENS ET AL M CONTROL SYSTEM FOR MOTIONPICTURE APPARATUS Nov. 10, 1942.

Patented Nov. 10, 1942 CONTROL SYSTEM FOR MOTION PICTURE APPARATUSCharles L. Lootens and Walden 0. Watson, North Hollywood, Calif.,assignors to Radio Corporation of America, a corporation of DelawareApplication December 2'1, 1940, Serial No. 371,982

11 Claims. (01. 8816.2)

This inventionrelates to motion picture apparatus and particularly to asystem for controlling the starting and stopping cycles of motionpicture cameras and sound recorders when operated simultaneously.

It is well known in the art of motion picture production that picturesare photographed at one location and the sound usually-recorded atanother location, the camera and projector being operated in synchronismat constant speed. Thus, the respective motors for the picture cameraand sound recorder should be simultane: ously started and operated Sinceone or more microphones are positioned about the set during the actualphotographing of the scene, it is necessary that extraneous noises beeliminated near or in the vicinity of the microphones to prevent thesenoises from being recorded with the desired sounds. Thus, warningsignalsin the form of bells, red lights and wigwags are employed. To aidin combining the two films into the final composite print, it is commonpractice to mark both the picture and sound negatives at the beginningand/or end of the take. This was formerly accomplished by the use of aclapperstick, although simultaneous light impulses have also been used.

The present invention is directed to a system for controlling thesequence of operation of the various warning lights and bells, thestarting of the camera and recorder, and the application of thesynchronizing marks to the respective negatives. In the past, thewarning bells, red lights and wigwags were manually operated, theoperator generally being a stageman who, on a verbal signal from anassistant director, would operate in synchronism.

the control switches located on the sound stage.

master switch, which started the recorder and camera motors and, as soonas the film loops had properly formed to insure constant uniform speed,the recording operator buzzed the go-ahead signal to the mixer on thepicture scene. The mixer then informed an assistant that the films hadreached constant uniform speed, and an assistant would hold theclapperstick in front of the camera and bring them together with a sharpsound to produce the synchronizing marks. The director then ordered theaction to start.

At the end of a take, the director would order out and the mixer buzzedthe recorders, who switched off the motors. The stageman then rang thewarning bells twice and switched off the red lights and wigwags, and thewhistle men blew their whistles twice. The recording operator would thenrun the recorders at the end of each roll of film for about five feet toexpose a density test. Since each of these operations was manuallycontrolled, considerable time was required to make a take. Also, sinceeach operation depended upon an operator, many violations occurred,resulting in numerous sound scenes being spoiled by extraneous noises orerrors.

The present system, in addition to furnishing positive control ofsignal, starting, marker and test devices, has eliminated the work ofswitch control men on the stages or on location, and also the whistlemen who supplemented the warning lights. The present systemautomatically controls all these operations, the starting cycle beinglisted, in the order of the occurrence of the operations, as follows:

(1) Warning red lights turned on,

(2) One warning bell sounds,

(3) Recorder and camera motors started,

(4) Synchronizing marks applied to the recorder and camera films.

At the end of a take, the following operations are automatically broughtabout, some of which occur simultaneously:

(1) The warning red lights are turned oil,

(2) Two warning bells are sounded,

(3) Density test is exposed on the recorder film,

(4) Synchronizing marks are applied to the re corder and camera films,

(5) The sound recorder and camera motors are stopped.

The principal object of the invention, therefore, is to facilitate thetaking or a motion picture and the recording of the concomitant soundtherefor.

Another object of the invention is to automatically control the seriesof operations required for photographing a motion picture scene andrecording the sound therefor.

A further object of the-invention is to eliminate the manual control ofvarious operations required at the beginning and end of thephotographing and recording or a motion picture scene.

A further object of the invention is to automatically control warninglights and bells, the starting and stopping of cameras and soundrecorders, and the application of synchronizing marks in thephotographing of a motion picture scene and in the recording of thesound therefor.

A further object of the invention is to'generate an alternating currentmarking signal which controls a signal for indicating the satis factoryapplication of the marking signal.

Although the novel features which are believed to be characteristic ofthis invention will be pointed out with particularity in the appendedclaims, the manner of its organization and the mode of its operationwill be better understood by referring to the following description readin conjunction with the accompanying drawings forming a part thereof inwhich Figure 1 is a combination schematic and diagrammatic drawingembodying the invention;

Figure 2 is a development of the cam system employed in the invention;and

Figure 3 is an end view of one of the cams and relays operated thereby.

Referring now to Figure l, the upper portion of the circuit shown withinthe dotted lines comprises an oscillator and thyratron circuit employedfor generating marking currents and signal currents for indicating thatthe marking system has operated. The oscillator comprises a doubletriode tube 5, the plates of which are fed back through condensers 6 andl to the grids in the opposite triode sections. The grids are tuned to,2000 cycles by the parallel resonance circuit comprising inductances 9and a condenser lil. The output of the two plates of the tube is fed tothe primary of an output transformer l2.

The oscillator is supplied with power through a rectifier unit includinga power transformer i I, the primary of which is connected to a sourceof ll0-volt alternating current at terminals l3, and a full-waverectifier tube H. The output of the rectifier is filtered through aninductance i6 and condenser ii, the latter of which is shunted by ableeder resistance I8, the bleeder resistance preventing excessivevoltage across condenser ll during the time the oscillator gridcathodecircuit is open. It will be noted that the grid-cathode circuit isconnected over conductors to contact switch 2|, the closing of theswitch 29 starting the oscillator in operation.

The secondary of the output transformer i2 is connected through theprimary of a coupling transformer over a network composed of aballast-lamp 25 and a fixed resistor 26, this network "being provided toproduce a voltage differential sufiicient to operate the thyratron witha three-marker unit load but not with a twomarker unit load, as will beexplained hereinafter. Connected in series with the respective secondaryand primary terminals of transformers l2 and 24 is a series resonancecircuit composed of inductance 28 and a condenser 29 which is sodesigned as to have minimum insertion loss at 2000 cycles and maximuminsertion loss at sixty cycles, thus preventing the sixtycycle powerfrom operating the thyratron. Connected in shunt across conductors ii isa series resonance circuit comprised of an inductance 32, a condenser33, and a. marking lamp 34 which may be connected in and out of circuitby a switch 35. This lampl circuit is a duplicate of the marking unitsemployed in the camera and recorder, is tuned to 2000 cycles, and isdisconnected only when three marking unlts are being used, such as twocameras and a recorder.

It will be noted that conductors 3! are connected to two wires of afour-wire cable 36 interconnecting a sound recorder 31 and a picturecamera 38. One of these connectors is a ground wire required forprotective purposes and is also employed in other cables, while thesecond conductor for the marking currents is one of the main conductorsof the three-phase power supply system. Since the oscillator issupplying a 2000-cycle current, this method of transmitting themarkingcurrent has been found satisfactory and economical.

As mentioned above, a shunt circuit similar to the unit comprisingelements 32, 33 and 34 is employed in the recorder 31 and the camera 38.Upon impression of the 2000-cycle current, the lamps corresponding tolamp 34 are energized and the respective films are fogged. All thesemarking lamp circuits are designed to attenuate the sixty cycles fromthe three-phase supply line to the lamp, while having a minimumattenuation to the 2000-cycle current. Thus, it will be obvious that theclosing of contact 2!, which starts the oscillator 5 into operation,will impress a 2000-cycle current upon the recorder and cameraenergizing the respective fogging lamps thereof.

The three marking lamps, namely, lamp 34 and the ones in the recorderand camera, are normally connected in the circuit. Now, in accordancewith the amount of current drawn by these three circuits, the resistanceof resistor 26 is adjusted so that the current through lamp 25 is at apoint on the temperature-resistance characteristic where the resistancechange is rapid for a decrease in the current through the lamp. Thisadjustment produces sufiicient voltage across the secondary oftransformer 24 to oper ate the thyratron. Now, should one of the markerlamps burn out, the decrease in current through lamp 25 is accompaniedby a large drop in voltage across the lamp, this voltage reaching apoint below which the thyratron will operate. Thus, the network 25-26controls the voltage to the thyratron so that it will operate with threemarking lamps in circuit but not when only two are functioning.

Referring now to the right-hand portion of the circuit within the dottedlines, there is shown a thyratron relay tube 43, connected to the stepuptransformer 24. The secondary of the transformer 24 is tuned to 2000cycles by a parallel resonance circuit consisting of a condenser 40 andan inductance 4|. A potentiometer 42 is provided for adjusting theoperating limits of the thyratron tube 43 in conjunction with network2526. The thyratron portion of the circuit is supplied with powerthrough a transformer 44, the primary of which is connected to a -voltsixty-cycle source at terminals 46. This transformer 44 supplies afilament voltage and a bias voltage to the thyratron tube 43. The biasvoltage is out of phase with the 110- volt sixty-cycle A. C. deliveredto the plate 01 the thyratron, this bias being adjusted to a point belowthe igniting point. The bias voltage is fed to the grid of the tube 43through a delay network composed of resistances 48 and condensers 49.This timing circuit increases the duration of the firing time andprevents the thyratron from firing for one cycle only. Connected in theplate circuit of the thyratron 43 is a rality of condensers 52, thisnetwork preventing chattering of the contacts 53 of a relay 54. Thecontacts of relay 53 are connected to conductors 55 which are connectedto a buzzer 51 at the camera, and a buzzer 58 at the recorder, energizedthrough a source of power such as a battery 59.

The operation of the above-described portion of the system is that, uponthe closure of the contact 2|, the oscillator begins generating 2000-cycle current which is impressed upon the recorder and camera marking orfogging lamps and lamp 33. If all of these lamps are operatins. then theproper voltage will be supplied to thyratron 43 to ignite it, causingthe relay 54 to be energized, closing contact 53, which energizesbuzzers 51 and 58 to indicate that the marking lamps have beenenergized.

Referring now to the lower portion of the system, a'inotor, such as asimple clock motor 61, has a. brake B2 and is adapted to drive aplurality of cams 63, 84, 55, 56 and 61. This motor may be supplied withenergy from either a D. C. or A. C. source connected to terminals 59.The power supply circuit from terminals 69 is over a three-wire circuitcomposed of conductors I0,

' II and 12. The blade 14 of a three-way switch controls the starting ofthe motor 5|, while the position of the swinger of switch 13, operatedby cam 61, controls the stopping of the motor. Thus, the throwing of theswitch blade 14 to the lower contact position will start the motor 6| toits lower contact by the cam El, the motor will be deenergized but maybe started again by Zhrgwing the switch blade H to its upper con-Simultaneously with the operation of the switch M, blade 76 is actuated,the lower position of which will energize a plurality of lamps orwigwags 58. That is, the lamps lii indicate red warning lights which maybe positioned at the doors of stages or other places to indicate that ascene is being photographed, or they may represent moving wigwags orsignals which may be positioned in the streets about a stage to stoppedestrians or motor trafiic. Thus, the swin ing of the switch blades74|'6 to their lower position to start a take-will start the motor SIand simultaneously turn on the signal lights 18, while the throwing ofthese blades to their upper position will extinguish the lights I8 andwill start the stopping cycle of the motor 6!, as will be explained.

The rotation of the motor 5|, as mentioned before, starts a series ofoperations. Cam 53, shown in Figure l, operates a contact 80 whichenergizes a plurality of signal bells 8| through an energy source 82.These bells are positioned on the set or in other locations to servenotice of the beginning or end of a take. operates a contact 84 which isconnected over conductors 85 through an energy supply 85 to a relay 81.It will be noted that relay 81 shunts a manual three-phase switch 88connected to the main three-phase power supply for the recorder 31 andcamera 38. Both'the relay 81 and the manual switch 88 are connected to agroup of 75' Cam 64 start relays 89, which, in turn, are connected overconductors to the camera'and recorder. The starting relay system 88 issimilar to that disclosed and claimed in copending application SerialNo. 327,267, filed April 1, 1940, now Patent No. 2,282,957, issued May12, 1942. Thus, the closing of contact 84 will energize relay 8'! andimpress the three-phase power upon the starting relays 89, which willstart the recorder and;

camera, as disclosed in the above-mentioned copending application,

Cam 55 operates contact 2|, and, as explained above, will produce fogmarks on the negatives in the respective recorder and camera andindicate that such marks have been made. Cam 55 will operate contact 92,which energizes relay 93 for the purpose of increasing the lightexposure on the sound negative, which may be accomplished in variousways, such as by removing the galvanometer bias from the noise reductionshutters or by tilting the galvanometer itself. This operation occurs atthe end of a take for the purpose of exposing a density test strip forthe sound negative.

To show theconstruction of the cams 63-51, an end view of cam 61 isshown in Figure 3. It will be noted that this cam has a constant radiusover a certain percentage of its circumference, and another radius overthe remaining portion of the circumference. Thus, with the swinger ofswitch 13 located on the shorter radius, the upper contact of the motorcontrol switch will be closed; and, with the swinger on the largerradius, the lowercontact of the motor control switch will be closed. Theother cams are constructed in the same manner, except that the dwellsare over different portions of the respective circumierences, while theother switches have only a single contact. Each of the switches ismounted on a block 95 with a contact screw 96, switch 13, however,having an extra back contact element S6 for operation in the three-wirecircuit.

To indicate the relative action of the five cams and the sequence ofoperation of the switches actuated thereby, a chart, shown in Figure 2,is submitted, this chart showing the development of one revolution ofeach of the cams to include the beginning and end cycles of a motion picture sound take. Starting at the ieft-hand side of the chart, with thechart moving toward the left in a time interval of approximately fifteenseconds, it will be noted that a short coast section is shown for theciock motor cam 61, the

purpose of which will be explained later. However, upon the rotation ofthe cam, the first contact to be made is 80, which will energize thebells 8|. These bells will ring once for approximately two seconds toindicate the beginning of a take, at the end of which time contact 84 isclosed to energize relay 81 to start the recorder and camera motors. Atabout one hundred twenty-three degrees of rotation, or approximate- 1ythree seconds, the motors are up to speed, and

.cam 65 closes contact 2| to operate the oscillater to providesynchronizing marks on the respective negatives. If the marker circuithas properly operated, the relay contact 53 will cl se and the buzzers51 and 58 sounded to indicate that the films have been marked. At thecompletion of the buzzer cycle, the upper contact of switch 13 is brokenand the motor 5! and the cams are stopped. However, even though thebrake 62 is applied, the inertia of the rotating elements will rotatethe cams over the coasting section of six degrees, which causes thelower contact of switch 13 to be made. After the buzzer signal, theaction begins before the camera, and the scene is photographed.

At the order from the director to cut," the switch blade 14 is manuallythrown to its upper contact and the motor 6| is started, which againstarts the cam rotating. The throwing of the of twenty-one degrees, overwhich period the contact 2| is closed to again mark the respectivenegatives in the recorder and camera. Simultaneously, the contact 92 isclosed, actuating relay 93 and increasing the exposure on the soundnegative for a density test. As the cams continue to rotate, all thecircuits are deenergized except the motor circuit to the motor 6|, whichcontinues to operate until it completes one revolution, at which timethe lower contact is broken and the motor is stopped. The motor and camscoast sufiiciently to close the upper contact of switch 13, readying theapparatus for the next take.

Thus, from the above, it is apparent that it is only necessary for anoperator to operate one switch such as 'l4l6 to initiate a sequence ofoperations which formerly required several manual operations with acorresponding number of operators. Furthermore, the sequence ofoperations is uniform and dependable, there being no opportunity formanual errors to be injected in the system. The synchronizing marks arealways placed at a certain position on the fihn where the cutters oreditors know where to look for them. Also, the marking circuit isautomatic to the extent that, unless the films are properly marked, thego-ahead buzzer signal will not be given. Thus, this automatic startingand stopping system for picture cameras and sound recorders hasmaterially reduced the time required to photograph a scene and recordthe sound thereof and has produced a higher average of good takes thanwas formerly obtainable with past methods and systems.

What we claim as our invention is:

1. An electrical control system comprising a motion picture camera, asound recorder, signaling apparatus, means for simultaneously markingfilms in said camera and recorder, and means for controlling thesignaling apparatus, the starting of said camera and recorder, and themarking of the films in said. camera and recorder in a predeterminedsequence and over respective predetermined time periods, said markingmeans including means for indicating that said films have been marked.

2. An electrical control system for motion picture apparatus comprisinga motion picture camera, a sound recorder, a power supply, means forconnecting the motors of said camera and recorder to said power supply,means for indicating the starting of said camera and recorder prior tothe connecting of said motors to said power supply, marking means forsimultaneously impressing light on the films in said camera and recorderafter said motors reach constant speed, means for indicating that saidfilms have been lightimpressed, and means for automatically actuatingall of said above-mentioned means in the above-recited sequence.

3. An electrical control system in accordance with claim 2 in which saidmarking means includes an electrical current oscillator adapted to bestarted in operation by said sequence actuating means, and said lightimpression indicating means is an electronic valve adapted to beoperated upon the proper functioning of said light-impressing means.

4. An electrical control system 'in accordance with claim 2 in whichsaid last-mentioned means comprises a plurality ofsimultaneouslyrotatable cams and a corresponding plurality of electrical switchesoperated by said cams when said cams are rotated, and means for rotatingsaid cams, one of said switches controlling the stopping of said meansfor rotating said cams.

5. A control system for a motion picture camera and recorder comprisinga power source, means for connecting said power supply to said recorderand camera, means for indicating at a remote point the operation of saidrecorder and camera, means for momentarily light-exposing the films insaid camera and recorder, means for indicating that said films have beenmomentarily exposed to light, a plurality of switches for controllingthe operation of all of said means, and automatic means for actuatingsaid switches in a predetermined sequence and over predetermined timeintervals.

6. An electrical control system in accordance with claim 5 in which saidlast-mentioned means includes a plurality of cams adapted to operatesaid switches in accordance with the angular position of said cams, anda motor for rotating said cams, .one of said cams deenergizing saidmotor after it has been manually energized.

'7. A system for controlling the starting and stopping cycle of a motionpicture take comprising a plurality of signal lamps at a remote point,means for energizing said lamps, a plurality of audible signalingdevices, means for energizing said devices, a power source, a picturecamera, a sound recorder, means for connecting said source to saidcamera and recorder after said audible signaling devices have beenenergized, means for simultaneously exposing the films in said cameraand recorder to light, said last-mentioned means including means forindicating the operation of said exposing means, means for actuating allof the said energizing, connecting and exposing means, and means forautomatically controlling the sequence of operation of said actuatingmeans after said lastmentioned means has been manually operated.

8. A system in accordance with claim '7 in which said controlling meanscomprises manual means for starting said controlling means, andactuating means controlled thereby for stopping said controlling means.

9. An automatic system for starting and stopping a plurality of motionpicture cameras and recorders having respective driving motorscomprising an energy source, a plurality of cams. a motor adapted torotate said cams when said motor is energized, manual means forcontrolling the energization of said cam motor, and a plurality ofswitches operated by said cams in accordance with the angular positionof said cams, one of said cams and switches operated thereby controllingthe energization of said camera and recorder motors, and another cam andswitch controlling the stopping of said cam motor at a predeterminedposition of rotation of all of said cams, said camera and recordermotors being deenergized by said respective cam and switch after saidcam motor is reenergized.

aao pu 10. A control system for a motion picture camera and a soundrecorder, comprising a power source for energizing the motors in saidcamera and recorder, visual signaling means, audible signaling means,marking means for both of said films, means for exposing only one ofsaid films, means for connecting said motors with said power source,means for energizing said visual signaling means, said audible signalingmeans, said film marking means, and said film exposure means, means forautomatically con-' trolling the operation of all of said means in apredetermined sequence, and means for simultaneously energizing saidautomatic means and said visual signaling means, said automatic meansfirst actuating said energizing means for .erating of said light

